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    4+1 Views for a Business Cooperation

    Framework Based on SOA

    Anca Daniela Ionita, Monica Florea and Lucian Jelea

    Abstract The paper analyzes LD-CAST, a business

    cooperation framework for automated or semi-automated

    business services, realized by various processes that orchestrate

    late bound Web services. The 4+1 Views Architecture proves

    to be appropriate for the analysis and design of systems with

    complex objectives, like: user friendliness for multiple actors;

    maintainability and extensibility under business evolution

    conditions; flexibility for dynamic retrieval of service

    providers; performance traceability for software and users. The

    paper presents the correspondences established between

    use-case, process, logical, implementation and deployment

    views, such as to attain these objectives, and to hide the

    back-stage complexity for the business domain users. The

    solution is based on three pillars: Service Oriented Architecture

    (SOA), Business Process Modeling (BPM) and semantic Web.

    The three of them are also used for comparing our system with

    other similar works.

    Index Terms e-Business, Service Oriented Architecture,

    UML Modeling, Web Service Orchestration

    I. INTRODUCTIONThe new way of doing business stands in an increasing

    interaction inside the business community, by directly

    creating and maintaining partnerships between individual

    companies, community organizations and social

    entrepreneurs. Businesses of all sizes need to interact to each

    other, but also to public authorities [1] - in a friendly and

    transparent way, supported by new cooperation frameworks

    for Business to Government (B2G). The new alliances may

    be easier established in a homogenous environment, where

    social partners may interact with trade unions, regional and

    international governmental organizations and a wide variety

    of other civil society organizations and networks. Currently,

    the state of the art is still characterized by non-homogeneity

    related to legislation, terminology and procedures, but also to

    the technical environments, due to different data structures,

    communication protocols or semantics.

    Manuscript received September 26, 2009. This work was supported in

    part by the European Community, under the FP6 IST Programme,

    FP6-2004-IST-4-26919 project (LD-CAST) and in part by CNCSIS,

    Romania, under the Grant IDEI 627/2009.

    A.D. Ionita is with the Computers and Industrial Informatics Department,

    University Politehnica of Bucharest, Spl. Independentei 313, 060042,

    Bucharest, Romania (phone: 4-021-4029113; fax: 4-021-3181014 ; e-mail:

    [email protected]).

    M. Florea is with SIVECO ROMANIA SA, Victoria Park, Sos.Bucuresti-Ploiesti 73-81, 013685, Bucharest, Romania (e-mail:

    [email protected]).

    L. Jelea is with SIVECO ROMANIA SA, Victoria Park, Sos.

    Bucuresti-Ploiesti 73-81, 013685, Bucharest, Romania (e-mail:

    [email protected]).

    Interoperability frameworks are being created for the

    cooperation and integration of public institutions, as well as

    for supporting business development, with the attention to

    address organizational, semantic and technical issues [2]. An

    important commonality of these platforms is that they are

    based on electronic services, which are developed for a large

    variety of applications, dedicated to citizens, businessmen,

    civil servants, medical staff or teachers. Service engineering

    involves cooperation of multiple tools and actors, not onlyfor the front-end business specific functionality, but also for

    the back-end architecture, which attains a high complexity

    due to the requirements of managing processes and

    ontologies, maintaining smart service repositories,

    discovering services automatically and supporting security.

    The present e-Business systems are confronted to a lot of

    challenges. Heterogeneous types of business services have to

    be integrated into seamless processes - at local, national, and

    Pan-European levels - eliminating the loose electronic

    integration of activities for Service Providers (SPs) from

    different European countries and regions. Documents,

    processes, and services have to be defined with no ambiguity.The automation of the request resolution inside SPs needs

    improvements, as well as the validation and monitoring of

    services and processes provided by multiple SPs. One has to

    attain flexibility in service/process reconfiguration and

    maintenance and to dynamically propagate changes of

    semantic definitions to registered services and processes.

    Personalized and easy-to-use interfaces are required for

    non-IT personnel. Automatic guidance is needed for all sorts

    of users, especially for non-specialist ones.

    The scope of this paper is related to business development

    in the context of the enlarged Europe, in connection with the

    e-service frameworks existent at national levels. In order to

    implement trans-border processes, one has to surpass the

    difficulties related to:

    - multi-actor environments that require multilateralagreements;

    - non-homogeneity of security policies of the involvedinstitutions;

    - non-interference with the internal work ofadministrations, enterprises or institutions that deliver

    services;

    - necessity to create strong multilingual facilities forcustomer-oriented services, processes and tools.

    The technical problems arise from the necessity to create

    large-scale distributed systems that may be accessed through

    a unique, one-stop portal, hiding the existent

    non-homogeneity of procedures, document formats and

    legislations among European countries. Service Oriented

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    (Advance online publication: 19 November 2009)

    mailto:[email protected]:[email protected]
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    Architecture [3] offers possible solutions for these problems,

    by supporting atomic and composite services, eventually

    delivered by multiple cross-border service providers.

    Semantic non-homogeneity can be treated by defining

    ontologies [4] that characterize generic processes, abstract

    Web services and service providers from various countries,

    as well as common quality of service (QoS) notions,

    necessary for establishing service level agreements.

    Sometimes, correspondences between local ontologies

    (either regional or national) and central, European level ones

    [5] have to be defined, implemented and maintained.

    The aim of LD-CAST system [6] presented in this paper

    was to support the development of private company

    initiatives, belonging either to private or public sectors, by

    cross border cooperation between European Chambers of

    Commerce (CCs). A one-stop portal at European level is

    dedicated to existent and new start-up enterprises, created by

    investors or entrepreneurs interested in an innovative line of

    business, based on trans-national development and growth.

    The semantic interoperability between different CCs acting

    as service providers is assured by an ontology containing

    common, core elements, which are then specialized on

    national-specific concepts. The technical interoperability

    stands in the framework developed for modeling, executing

    and monitoring business processes that seamlessly compose

    and localize services delivered by different institutions, from

    different countries, while respecting their specificities,

    procedures, as well as privacy and security rules and

    regulations.

    The paper describes the LD-CAST system in chapters II

    and III, using UML 2 models [7], organized according to 4+1

    Views Architecture [8]. It also presents the correlations

    between these views, outlining the interoperation between

    subsystems accessible to business domain users and those

    hidden to them, dedicated to actors responsible for the system

    configuration and maintenance (more details in chapters IV

    and V). Chapter VI treats configuration and maintenance

    issues and chapter VII analyzes some works that are related

    to LD-CAST approach, many of them also supported by

    European projects.

    II. ABUSINESS COOPERATION FRAMEWORK BASED ON SOAThe European market analysis highlights the strong

    presence of partnerships at trans-national level. In this

    context, the main advantages of supporting new interaction

    patterns are:

    - creating new opportunities for training, placements,mentoring, and leadership development;

    - improving operational efficiency;- helping institutions to grasp new opportunities;- increasing access to financial, technical and managerial

    resources;

    - enhancing effectiveness and credibility.Moreover, there are supplementary advantages that might

    be brought by a trustworthy system, offering a cooperation

    framework of cross-border services to enterprises andentrepreneurs:

    - supplying a large spectrum of information related to thebusiness support existent in various countries;

    - using a common terminology;- saving the client time, by delivering documents

    and/or services without the necessity to reach the local

    sites of chambers of commerce or other institutions;

    - assuring a secure access.To attain these goals, the system has to provide an

    organizational, semantic and technical interoperability, as

    specified in the European Interoperability Framework[2].

    The scope of a business cooperation system coversactivities like business set up, certification, company

    information, promotion, training, investment towards and

    from foreign countries, supplying socio- economical data and

    supplying access to on-line services. The difficulties to create

    an homogenous environment for them are due to the different

    degrees of technological development of public

    administrations and to the fact that, currently, most of the

    services provided by the chambers of commerce are

    delivered at the desk, while only few on-line services are

    available.

    One of the important tasks of LD-CAST project was to

    create unifying concepts and tools regarding various

    cooperation aspects, like cooperative business, compatibility

    of statutes, communication protocols and common

    repositories. The compatibility from the point of view of

    terminology was also a key issue; hence, the multilingual

    interface of some tools and the creation of a common

    business glossary, such as to avoid lexical ambiguities. The

    technological incompatibilities were smoothened by

    choosing service oriented architecture.

    To take advantage of the business cooperation system, an

    entrepreneur or an SME would have to get registered at one

    of the local agencies, which act as connection points and as

    identity providers, and have responsibilities regarding the

    access of the local users, the payment and the provision ofinformation regarding the available services. After

    registration, they implicitly become LD-CAST End-Users,

    entitled to access the following functionalities:

    - browsing, selecting and requesting for complex businessservices;

    - making choices related to the preferred configurations,particularly related to cost and time;

    - delivering and receiving documents;- monitoring the execution of business processes;- communicating with the platform administrator.

    In order to offer this support for the business parts, the

    framework uses Web services delivered by external service

    providers, and orchestrate them according to specificprocesses, in order to execute the requested business service.

    Therefore, other important functionalities stand in:

    - defining and publishing Web services deployed byservice provider registered at LD-CAST;

    - defining and publishing processes that base theirexecution on the orchestration of the available Web

    services.

    One of the most important requirements of LD-CAST was

    to map process activities on actual services at run-time, not at

    design time, for increasing the system flexibility. For this

    purpose, both services and processes are annotated according

    to a common business ontology, and matchmaking can be

    performed dynamically.

    For the administration of the framework, the main

    functionalities are:

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    - monitoring system performance and quality of service ofthe service providers;

    - fulfilling security requirements.This subchapter has briefly the requirements of LD-CAST

    informally; the following one is applying the 4+1 Views

    Architecture to describe the way the system was developed.

    III. 4+1VIEWS FORLD-CASTFRAMEWORKViewpoint-oriented approaches have often been used in

    requirements engineering, to be able to treat the needs of

    various stakeholders [9]. Moreover, they have been useful for

    designing the architecture, as it is the case of the approach of

    Philippe Kruchten [10], applied in this paper, and also for

    developing based on separation of concerns and Aspect

    Oriented Software Development [11].

    LD-CAST system is presented below, according to the

    following 4+1 views (see Fig. 1):

    1) The Logical View representing structural elements,levels of abstraction, separation of concerns and

    frequently using object-oriented models;2) The Process View treating the execution aspects of the

    system: the interaction patterns and the concurrency;

    3) The Implementation View showing the decompositionin subsystems used in the development environment and

    originally called development view;

    4) The Deployment View outlining the distribution ofsoftware components on physical nodes, either

    computers or processors; it was originally named

    physical view.

    +1)The Use Case View illustrating the use cases orscenarios dedicated to multiple actors and further

    involving dedicated languages and tools, which are

    described in other views.The particularities of this system are related to SOA

    affecting the deployment. Moreover, the presence of the

    executable business processes gives a larger importance to

    the Process View and to the correlations between it and the

    others. Due to the generic character of the 4+1 view model,

    the paper uses UML diagrams as concrete notations.

    A. The Use Case ViewLD-CAST is mainly dedicated to serve entrepreneurs

    interests to obtain electronic business services, in order to

    save their time and money and to attain confidence related to

    unknown chambers of commerce and potential partners from

    abroad. Any Guest is able to obtain detailed informationrelated to business cooperation, but one has to register and

    become anEnd-User, in order to get advantage of the

    business services published within the framework (see the

    use case diagram in Fig. 2).

    However, LD-CAST system had to assure the dynamic

    discovery of Web services, taking into account the client

    preferences, the common descriptions for services and

    processes, and the respect of the subsidiary principle, by

    allowing each chamber of commerce to follow its specific

    procedures. In order to acquire these requirements, the

    system needs specialists with various competences for its

    configuration and maintenance.Business Process (BP) Designeris in charge of modeling

    specific processes, whose activities are to be implemented

    by Web services (see Fig. 3).

    Development View

    (Implementation)Logical View

    Process ViewPhysical View(Deployment)

    Scenarios

    Use Case View

    Fig. 1 Correspondences between the 4+1 Views

    Fig. 2 Use case diagram with non-specialist actors [12]

    Fig. 3 Use case diagram with actors involved in LD-CAST configuration and

    monitoring [12]

    The late mapping of activities on concrete services is

    realized through the concepts and relationships of the

    business ontology, created and managed by the Knowledge

    Engineer.

    Thus, the process is executed with actual Web services,

    selected from a repository where they had been published bypersons playing the role ofService Provider Administrator.

    The security and integrity of LD-CAST are assured by an

    LD-CAST Administrator, who can also monitor the clients

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    and the system performance.

    Even if the system was conceived to automate the delivery

    of business services, the practice revealed that some of the

    tasks still have to be performed manually; therefore, a Service

    Provider Clerkwas introduced, who can also monitor all the

    business service requests assigned to its service provider.

    B. The Logical ViewEach subsystem of LD-CAST has a complex data model.

    For the purpose of this paper, let us see the logical point of

    view standing behind the execution of a business service,

    which is a key issue for this framework. There are three

    layers [13], corresponding to different levels of abstraction

    and different technologies (see Fig. 4):

    - Modeling Layer- Abstract Execution Layer- Concrete Execution Layer.

    The Modeling Layeris situated at the highest level of

    abstraction and contains the following classes:

    - Business Service (BS) representing an intangible product achieved to fulfill a need or a goal; it ischaracterized by the defined inputs and outputs and by

    the quality of service;

    - Business Process (BP) a process that is associated to abusiness service and may render it executable;

    - Activity - is a part of the business process that may beundertaken automatically or manually by an

    entrepreneur, a commercial enterprise or a chamber of

    commerce.

    LD-CAST has identified the following business

    services that can be delivered by the chambers of

    commerce: Partner search, Company legal verification,

    Company fiscal verification, Technical and quality standardverification, Agreement, Registration, Mediation, Arbitration

    and Supply subcontract. However, each of them may be

    delivered by different chambers, from different countries,

    involving a 1-to-many correspondence between a business

    service and its business processes, defined by a domain

    expert playing the role of BP Designer.

    In order to automate these processes, they have to be

    transformed into executable workflows. As LD-CAST

    flexibility requirement imposes a late binding of Web

    services, there are actually two layers of execution.

    TheAbstract Execution Layercontains the classes:

    - Abstract Workflow a sequence of abstract services,corresponding to a business process, but introducing

    technical details, to allow the automatic generation of a

    Concrete Workflow;

    - Abstract Service - described by its functionality, inputand output; it is not directly executable, because it does

    not refer to a specific service implementation (a concrete

    Web service); it is defined at design time and it

    represents a set of Web services with the same

    functionality, input and output .

    The Concrete Execution Layer contains the following 2

    classes:

    - Concrete Workflow - a workflow for which eachabstract service has been replaced with a correspondentWeb service;

    - Web Service - an executable service representing a

    concrete service having the same functionality, input and

    output as the correspondent abstract service.

    The concrete workflow is determined at run time, by

    semantically searching the available concrete Web services

    that may implement the abstract activities. The service

    discovery introduces a first level of flexibility in the

    traditional way of modeling and executing processes: the

    business service is described in terms of abstract activities,

    ignoring the way a specific activity is implemented; there is

    no actual reference to the concrete service that realizes that

    activity. The Business Process Designer actually designs a

    template for the business process, which will be rendered

    executable at run time, after being requested by the

    End-User.

    C. The Process ViewThe process view of LD-CAST is rather complex; there are

    two kinds of processes that have to be descried in this view:

    - scenario processes corresponding to the use casesassociated to the system actors and represented as

    activity, sequence or communication diagrams; theyhave a descriptive role in the system analysis and design.

    *

    Business

    Service

    Business

    ProcessActivity

    Abstract

    Workflow

    Concrete

    Workflow

    1..*

    1..*

    1..*

    Abstract

    Service

    Web

    Service

    1..*

    Fig. 4 The logical view with the execution layers

    Fig. 5 Example of business process: Certificate with company data

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    - executable business processes used for configuring thesystem; the are represented with a specific language at

    the level of the Modeling Layer and then with BPEL at

    the Abstract and Concrete Execution Layers, to be able

    to be transformed into an executable workflow .

    Let us analyze in this paper the example of business

    process from Fig. 5, which is defined for supplying a

    certificate with legal or fiscal data related to a certaincompany. The legal verification may contain, in terms of the

    country, the certificate of existence, information about the

    joint stock, the corporate form, the business history, or a

    criminal report to know if the company has been involved in

    criminal acts in the past. The fiscal verification may contain a

    report about the main financial indicators, the full balance

    sheet and the regular pension contribution certificate.

    For such processes, some activities are executed

    automatically; others require the contribution of various

    actors. In our example, the End-Users interact for introducing

    inputs that personalize the request, for making the payment

    and for downloading the results. Ideally, the certificate is

    generated automatically and supplied through a Web service;

    currently, for some chambers of commerce it has to be

    supplied by the Service Provider Clerk.

    D. The Implementation ViewThe LD-CAST architecture is service oriented and all the

    connections between its subsystems, depicted in Fig. 6, are

    realized through Web services, using SOAP [14]. The

    subsystems accessed by each of the actors mentioned above

    are presented as follows.

    The Guest and the End-User work with the Run Time

    Portal for obtaining information and business services from

    LD-CAST. The portal is implemented with JEM (JBossEnterprise Middleware) [15] and performs its tasks

    dynamically, by interacting with other subsystems.

    The Business Process Designer uses the Business Process

    Modeler (BP Modeler) subsystem, for defining process

    models with ADOeGov [16] modeling language, which

    allows process activities to be linked with abstract workflows

    Fig. 6 LD-CAST subsystems and their connectors [12]

    written in BPEL4WS (Business Process Execution

    Language for Web Services) [17].

    The Knowledge Engineer uses the Ontology Management

    subsystem to create the reference business ontology, using

    OPAL (Object, Process, Actor Modeling Language) [18].

    An ontology gathers a set of concepts concerning entities,

    attributes, processes, together with their definitions and

    inter-relationships. The reference ontology, related to the

    chambers of commerce domain of expertise, is used for

    semantically annotating Business Processes and Web

    Services, i.e. for attaching an expression built in terms of a

    reference ontology. The semantic annotation is then used for

    enabling the searching capabilities, in order to retrieve the

    needed resources.

    The Service Provider Administrator accesses the Concrete

    Resource Management(CRM) subsystem, in order to store

    information about the service provider, as well as to register,

    annotate and publish the delivered Web services. Manual

    services delivered though LD-CAST by a clerk of the service

    provider (not automatically) - are also registered at CRM and

    consequently, all activities of a business process are treated in

    a uniform way. Information is stored in a repository that may

    be accessed by the Search and Discovery (S&D) subsystem,

    which is able to perform a semantic matchmaking between

    the set of available Web services and the abstract services

    corresponding to a requested business process. The

    configuration of actual Web services or manual activities that

    implement the workflow activities is not fixed in advance,

    but established through a selection made by the End-User at

    run time, according to their registered cost and time. Thus,

    one supports a late binding and the generation of concrete

    BPEL workflows, whose execution is performed by the

    Process Execution Management(PEM) subsystem, using the

    ActiveBPEL engine. S&D and PEM do not interact directly

    with any of the system actors.

    The Security subsystem supports a federated identity

    solution for authentication and authorization, based on

    Shibboleth [19]. LD-CAST relies on the definition of a circle

    of trust with its local agencies - where End-Users are

    registered - while the management of other groups of users is

    performed directly, by the LD-CAST Administrator;

    moreover, he or she can also verify the system and the user

    efficiency, with the help of the Performance Monitoring

    subsystem, which collects logs from other subsystems and

    supplies a centralized monitoring console for the desired

    criteria.

    E. The Deployment ViewA primary reason for choosing SOA was the high degree of

    geographical distribution of LD-CAST, which is twofold. On

    one side, there is the deployment of the subsystems depicted

    in Fig. 6, which constitute theLD-CAST Core and for which

    the minimum number of nodes is 3, corresponding to the

    following platforms (see Fig. 7):

    1) TheModeling platform is dedicated to system set up andconfiguration, and can be accessed by actors like: BPDesigners, Knowledge Engineers, and SP

    Administrators. The following subsystems are part of

    this platform: Business Process Modeler, Ontology

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    Management and Concrete Resource Management.

    2) The Execution platform supports the automaticexecution of business services, by integrating the Run

    Time Portal, the Process Execution Management

    subsystem and the Search and Discovery one. Even if the

    portal is mainly dedicated to End-Users, it also allows

    the LD-CAST Administrator to manage its content, and

    supports the delivery of non-automatic services by the

    Service Provider Clerks, after introducing the proper

    credentials.

    3) The Administration Platform is used by the LD-CASTAdministrator to manage LD-CAST users (by

    interacting with Local Agencies - for End-Users - and

    directly - for the others); it also controls the efficiency of

    the system operation, using the Performance Monitoring

    subsystem.

    Actually, the prototype was deployed on more execution

    nodes, in respect with responsibilities assumed by different

    members of the project consortium for the development and

    maintenance of various subsystems, even inside the same

    platform. The SOA architecture allows this flexibility, in

    terms of optimizing the communication times of its

    connectors.

    On the other side, there are also two other kinds of entities,

    with their correspondent deployment nodes (see Fig. 7):

    - The Local Agencies: responsible for the payment and forthe local management of users that have access to the

    LD-CAST Core services; one becomes an End-User of

    LD-CAST and is able to request business services only

    after registering and identifying at a local agency,

    following its internal procedure; after that, the agency

    supplies its identity in the federated network.

    - The Service Providers: which provide manual and Webservices that will be orchestrated by LD-CAST Core, in

    order to satisfy an End-User request; they register and

    publish their services using the LD-CAST Core

    subsystems, through the SP Administrators.

    IV. CORRESPONDENCES BETWEEN VIEWSTypically, the use cases make the link between all the other

    views and, even if considered redundant information in the

    4+1 Views model, they are the first to be described. Thus,

    they clarify the usage of the system, especially when it is

    accessed by multiple actors and it has a complex structure.

    The Logical View may be vertically divided in complex

    data models for each subsystem, but also horizontally, into a

    layered architecture, as descried in Fig. 7. Different actors of

    the system are aware of different classes and different layers

    of abstraction. The Guest can only see the business services;

    the End-User can also see the names of the business

    processes, plus some information related to the concrete Web

    services that may be used for the execution, such as to be able

    to make a choice. However, the BP Designer can define all

    the details related to the business processes and their

    associated abstract workflows. The SP Admin accesses the

    lowest level of execution, because it registers the concreteWeb services in the repository.

    The Process View is very complex in LD-CAST, for two

    reasons:

    Fig. 7 LD-CAST deployment diagram [12]

    - due to the existence of 7 different kinds of actors, eachone with its rights and roles for using, configuring and

    maintaining the system;- due to fact that business services are explicitlyrepresented as processes, executed automatically and

    monitored by the framework.

    The execution of a business process involves the

    End-User, but also the SP Clerk. Moreover, the performance

    of the End-User and of the Web services is monitored by the

    LD-CAST Administrator. More details related to what

    happens in the back stage of this execution are given in the

    case study from subchapterVI.

    The Implementation View outlines that the subsystems

    have been specifically designed for different actors (see

    subchapter III). The non-professional actors can only access

    the Run-Time Portal, while the professional ones have tomodel and administer the system, so they are associated to the

    correspondent platforms from the Deployment View. The

    LD-CAST Admin works with Performance Monitoring and

    Security subsystems. The BP Designer configures the system

    with the BP Modeler. The Knowledge Engineer maintains

    the ontology with the Ontology Management subsystem and

    the SP Admin accesses the Concrete Resource Manager

    subsystem. Moreover, the SP Clerk, who is a business actor,

    not a technical one, also does his or her job through the

    portal, strictly contributing to the execution part.

    V. CASE STUDY FOR THE BUSINESS SERVICEMANAGEMENTSCENARIO

    For the purpose of the paper, one selected a typical

    scenario, correspondent to theBusiness Service Management

    use case (see Fig.3) with the correspondent activity diagram

    represented in Fig. 8.

    First, the End-User has to select the desired business

    service (e.g. Company Legal Verification) and the portal

    displays a list of processes that have been published for it,

    reflecting specificities characteristic for a certain country or

    even for a certain chamber of commerce. After selecting a

    process (e.g.Release Ordinary Visura , from Italy) the system

    searches the configurations of concrete Web services that can

    be used for the actual execution and gives detailed

    information about them, as shown in Fig. 9.

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    Fig. 8 Activity diagram for Business Service Management

    Fig. 9 Details related to a configuration of concrete services

    The End-User selects the preferred configuration and starts

    the execution of that business process, then monitors it, byactively getting involved in certain activities. At the end, it is

    possible to download the expected results, which have been

    stored in a repository of the one-stop portal.

    The case study analyzes the correspondences between

    elements of different views for the following activities:

    - Select Business Service,- Select Process,- Select Configuration and- Monitor Service Execution.A. The Activity Select Business Service

    For the activity Select Business Service, the actorinvolved is the End-User, while the logical concept is

    Business Service, situated in Fig. 4 at the highest level of

    abstraction.

    There are 2 correspondences to the Implementation View:

    - the Run Time Portal - which displays the list of businessservices and the description of the selected one (see Fig.

    10) and

    - the Business Process Modeler - from whom thisinformation is actually taken, as the content of the portal

    is created dynamically.

    Thus, this simple activity involves a process that goes

    across the Execution and the Modeling Platforms; thecommunication is performed with Web services.

    RRuunn TTiimmee PPoorrttaall

    Description of the selected business

    service

    Execution Platform

    BBuussiinneessss PPrroocceessssMMooddeelleerr ((BBPPMM))

    Fig. 10 Mappings for the activity Select Business Service

    RRuunn TTiimmee PPoorrttaall

    Description

    Execution Platform

    BBuussiinneessss PPrroocceessssMMooddeelleerr ((BBPPMM))

    Modeling Platform

    Fig. 11 Mappings for the activity Select Process

    B. The Activity Select ProcessThe tree from the left area of the portal can be expanded in

    order to display the names of all the objects of type Business

    Process associated to a business service (see Fig. 11); note

    that one still remains at the highest level of abstraction in the

    Logical View. The correspondences to the Implementationand Deployment Views are similar to the previous activity.

    C. The Activity Select ConfigurationEven if, from the point of view of the End-User, this

    activity is not different from the previous ones, it involves

    more complex interactions in the backstage, in order to allow

    the system flexibility and to take into account the user

    preferences.

    For the business process selected at the previous step, a

    correspondent abstract workflow has been previously

    implemented. It represents the control flow, with the

    sequencing of operations, but without concreteimplementations of the required activities. For creating a

    concrete workflow and getting at the third level of execution

    from the Logical View, the user has to choose the concrete

    services to which the system will bind the activities. A

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    configuration consists in a set of Web services that are

    registered at CRM and match to the abstract activities from

    the point of view of inputs, outputs and semantics. Thus,

    Run-Time Portal interacts with Search and Discovery, which

    uses a semantic matchmaking mechanism, based on semantic

    annotations performed on concrete services from CRM and

    business processes from BPM (see Fig. 12).

    Since there can be more than one Web service suitable for

    a given activity, the semantic search will return a set of Webservices. Thus, given a business process, there can be more

    combinations of concrete Web services (configurations)

    suitable for being executed.

    D. The Activity Monitor Service ExecutionThe End-User is not aware of the execution of Web

    services, nor of the workflows that orchestrate them. He or

    she needs a console (given by the Run-Time Portal) to

    monitor business service requests, checking their progress

    and status. The work is done at a high level of abstraction

    that of the business process, modelled with BPM.

    Moreover, the End-User has to interact with the system

    during the workflow execution, for instance for filling-informs, uploading documents, downloading results, or starting

    manual activities.

    The End-User is allowed to see information related to the

    processes that he or she had instantiated, whose states may

    be:

    - Executing,- Finished or- Errors.

    For each process it is possible to see the list of activities,

    whose states may be:

    - Not Started,- Started,- Finished,- Errors.

    Everything is deduced from the process state stored by the

    workflow engine of PEM subsystem (see Fig. 13).

    VI. CASE STUDY FOR THE PROCESS CERTIFICATE WITHCOMPANY DATA

    Even if scenarios are generally used for putting it all

    together, the Process View can also clarify the necessity of

    various subsystems used for the implementation, as well as of

    different nodes were they are deployed. This case study is

    oriented on the executable business process from Fig. 5,intending to show what is behind two of its activities:

    Payment and Supply Certificate. This process model,

    realized with BPM, was necessary because executable

    workflows are too complicated to be used by business experts

    and can not be designed by them directly. Therefore,

    LD-CAST used a metamodel of the process management

    domain and a friendly user interface. The studied activities

    can also be seen in Fig. 14, on the top level.

    The abstract workflow corresponding to this piece of

    model is also depicted at the second level, as represented with

    a BPEL Editor (see Fig. 14). For each process activity there is

    one correspondent abstract service (an activity that should

    call a Web service) and several concrete Web services that

    match (see the third level from Fig. 14).

    RRuunn TTiimmee PPoorrttaall

    SSeeaarrcchh && DDiissccoovveerryy

    Modeling Platform

    CCoonnccrreettee RReessoouurrcceeMMaannaaggeerr ((CCRRMM))

    BBuussiinneessss PPrroocceessss MMooddeelleerr ((BBPPMM))

    OOnnttoollooggyy

    Execution Platform

    Fig. 12 Mappings for the activity Select Configuration

    RRuunn TTiimmee PPoorrttaall

    Execution Platform

    PPrroocceessss EExxeeccuuttiioonnMMaannaaggeerr ((PPEEMM))

    Fig. 13 Mappings for Monitor Service Execution Activity

    Payment SupplyCertificate

    Fig. 14 Mappings for Payment and Supply Certificate Activities

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    This means that, for each one of the activities Payment and

    SupplyCertificate, there are 2 Web services registered at

    Concrete Resource Manager that may be called for the

    execution. For example, the activity SupplyCertificate may

    be mapped on 2 Web services (registered at CRM):

    - Company Certificate through Clerk a Web servicesupporting a specific interaction with SP Clerk, in order

    to obtain the results;

    - Company Data Certificate a Web service thatautomatically supplies a certificate.

    For the former, the requested certificate requires

    information that can not be automatically extracted from a

    database, as it often happens in real life scenarios; providing

    the service implies interaction with a clerk who had the

    possibility of producing and certifying the document, and

    then uploading it to the system to be later downloaded by the

    user. LD-CAST system registers this service at CRM and

    uses it in the execution of workflows as an alternative to the

    latter, which has a similar result, but obtains it automatically

    Furthermore, the system may be extended by plugging in

    new services, which have the same inputs and outputs and are

    annotated with the same concept from the ontology. Thus,

    building and then using an ontology related to the business

    service domain plays a fundamental role. The ontology does

    not only guarantee the mapping between the high level

    process activities and the Web services actually executing

    them, but it also allows business experts to continue working

    with meaningful concepts, abstracting from the technical

    issues.

    This process was used for testing the integration between

    the Modeling Platform and the Execution Platform. The

    process is published in the Modeling Platform and is

    retrieved from the Execution Platform, by the Run-Time

    Portal, after the End-User selects it. It has a correspondentabstract workflow stored in Process Execution Manager

    which has to be transformed into a concrete workflow, such

    as to be executed on the Workflow Engine from PEM. For

    this purpose, PEM interacts with Search and Discovery

    subsystem, which gives a list of possible configurations of

    Web services that might implement the abstract workflow;

    the example involves 4 possible configurations. The

    End-User selects one of these configurations through the

    Portal and then PEM transforms the abstract workflow into a

    concrete one and starts its execution.

    VII. CONFIGURATION AND MAINTENANCEFor being able to support a typical scenario, as described

    above, the Run Time Portal requires services from:

    - the Security subsystem, to get the user credentials;- the BP Modeler, to get the list of business services and

    the descriptions of the processes published for them (an

    extract of the exchanged information in XML format is

    given in the Appendix);

    - the Process Execution Manager, in order to start andmonitor the execution of a concrete workflow, selected

    by the End-User;

    - the Search and Discovery subsystem, to get the list ofconfigurations available for building a concrete

    workflow;

    - the Performance Monitoring subsystem, in order tosupply information about End-Users operation and

    statistics related to the requested configurations,

    business processes and business services.

    The Run Time Portal has the biggest coupling in the system.

    LD-CAST has to be properly configured in order to allow

    a coherent operation. On one side, for the desired business

    service, at least one process has to be modeled with BP

    Modeler, has to be annotated with concepts of the Ontology

    and has to be associated with an abstract workflow. On the

    other side, for assuring the executability, for each abstract

    activity there should be at least one concrete Web service that

    has been registered at CRM, annotated similarly as the

    activity and published. Then, the business process can also be

    published, in terms of existing at least one concrete workflow

    corresponding to it.

    LD-CAST has been designed as a system that is highly

    adaptable to change, as the system has to evolve in the

    rhythm of the business domain. Some important facilities for

    maintaining LD-CAST are: adding new concepts in the

    ontology (performed by the Knowledge Engineer); defining

    new processes (by the BP Designer); registering new Web

    services (by the SP Administrator); accepting new local

    agencies and service providers (by the LD-CAST

    Administrator) [20]. The difficulty stands in keeping the

    system coherent, under the conditions of multiple subsystems

    and multiple actors involved in the extension of the system.

    At the same time, the End-User must be oblivious to the

    existence of all the subsystems behind, but should notice the

    benefits gained through the potential of increasing the

    number of available business services and configurations

    corresponding to them.

    VIII. RELATED WORKSA. Works based on Service Oriented ArchitectureThe emerging electronic society has forced the

    development of SOA systems [21], where electronic services

    may be provided by: governments, business companies or

    even by consumers or individuals, and may be consumed by:

    other governments, business parts, consumers or by

    employees and citizens. Taking e-Business as example,

    information technology got involved in a large variety of

    business functions, like sourcing and procurement, design

    and production, logistics and distribution, marketing and

    sales, customer service [22]. Besides, a lot of European projects have adopted architectures oriented on services;

    some examples are commented below.

    SOA4ALL [23] aims to develop a domain-independent

    service delivery platform, seeing SOA as the emerging

    dominant paradigm for application development. The

    integration is based on a Distributed Service Buss and the

    basic functionalities and activities are supported by platform

    services. On this basis, the final users provide Web services

    and light-weight processes and are able to monitor their

    whole lifecycle.

    BREIN [24] supports the realization of virtual

    organizations for business-to-business collaborations, using

    a Modeling Framework based on SOA. Some importantcontributions are related to an enhanced management of

    service level agreements [25], using semantic descriptions,

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    and to automatic reactions to service failures for increasing

    the reliability of consumers.

    ALIS goal is to develop an innovative system in order to

    provide European citizens and private companies with a

    transparent, fast, secure and reliable access to the European

    Legal Knowledge. The main service-provision component in

    its architecture is the Legal Reasoning Engine (LRE) which

    is deployed on a service-oriented architecture for assuring the

    accessibility within e-Societies [26].NEXOF-RA [27] is a strategic project building a Reference

    Architecture for a generic open platform facilitating the

    collaboration between service providers and third parties.

    Generally, a new concern is to create user-centric instead

    of program-centric SOA, such as to enable a large

    deployment of services. Web 2.0 provides new

    methodologies regarding the way user interacts with Web

    applications. The semantic enabled services solve a great deal

    of the back-end problems, defining formally the meaning of

    information and services, but other complications may result

    at different levels.

    A difficulty encountered in LD-CAST was that the userinterface cannot be designed statically, but has to be adapted

    in respect with the input and output formats of whatever new

    services registered to the system when it evolves. Moreover,

    service orchestration [28] leads to the creation of composed

    services, involving composed input and output forms, whose

    configurations is not known in advance, but is decided by the

    End-User, at run time.

    A similar requirement can be observed in SEGOF project

    [29], which proposes a way to generate e-Government forms

    semi-automatically, based on semantic descriptions of public

    administration services and their business rules.The project

    focuses on automatically identifying relevant input for aPublic Administration Service based on the semantic

    description of the service and its business rules, which must

    be applied to create the particular results. According to the

    relevant input, a web-form is generated to gather the needed

    information from citizen. This input is interactively checked

    against the procedure business rules. If the provided data is

    correct and conforms to the ontology restrictions, it is

    represented as XML and RDF and can be consumed by any

    application supporting the data interchange standard,

    including semantic Web services.

    The guiding principles for the future front-end

    technologies are: empowering end-users to select, create,compose and customize their own services; detecting

    contextual information to adapt seamlessly to each situation;

    using End-Users knowledge to improve service front-ends;

    enabling collaboration between employees, customers,

    developers and providers [30]. One example may be FAST

    project [31], which provides a visual programming

    environment, supporting composition of services and

    definition of business processes from a top-down user-centric

    perspective, while in the back-end there are semantic Web

    services.

    B. The Role of Semantic TechnologiesLoose coupling can be considered one of the main

    requirements in the development and implementation of a

    service-oriented system. The main motivations in developing

    a loosely coupled application are the benefits of extendibility,

    reusability, interoperability and modular maintenance. From

    a technological point of view, the challenges of these

    requirements are usually overcome by enhancing SOA with

    ontology management systems.

    In particular, for avoiding predefined mappings between

    abstract and concrete services and for taking into account

    quality criteria and user choices, SOA generally uses

    Semantic Web Services. The role of semantic Web for

    assuring interoperability inside highly distributed systems

    has also been outlined by other European projects.

    BRITE project [32] uses ontologies to mitigate semantic

    heterogeneity of information, data and processes, supporting

    proactive information delivery and coping with multiple

    levels of formality on information and data levels.

    SAKE [33] adopted a semantic-based change management

    inside their collaborative and knowledge space dedicated to

    public administrations.

    SEEMP [5] investigated interoperability between

    non-homogenous e-Government systems for the employment

    sector, pertaining to different countries among Europe. Their

    solution for resolving heterogeneity was to convert all the

    XML semantic content in terms of a reference ontology,

    shared by all partners, and then to lower it back to an XML

    corresponding to a different local ontology. Technologically,

    this is achieved using the WSMX Data Mediation [34].

    SemanticGov project [35] utilizes the WSMO framework

    (implementing WSML ontologies) and Governance

    Enterprise Architecture (GEA) models for functionally

    restructuring public administration services and enhancing

    interoperability.

    C. Executing and Monitoring Business ProcessesAnother important issue in LD-CAST was that business

    processes have to be defined at a high level of abstraction, by

    business domain experts, but they have to be rendered

    executable, in order to assure the proper user friendliness of

    the system.

    A possible solution, adopted for Apel [36], is to create a

    Domain Specific Language (DSL) for defining process

    models and to use the DSL interpreter as execution engine.

    Another solution (adopted in LD-CAST also) is to use a

    specific language for defining business processes and then to

    translate it into executable BPEL workflows, for which

    execution engines already exist. In this case, the problem is

    that automatic generation of BPEL code encounters a numberof limitations: different process engines require different

    workflow code, and domain-specific models need complex

    graph transformation algorithms, for coming from a

    graph-based to a block-based structure.

    Important achievements were obtained in AgilPro project

    [37], where one uses a generation framework for a

    component-based design, which fosters reuse and

    composition for parts of generation solutions. The

    generation framework aims to enable people with no or little

    experience in programming or workflow technology, to

    generate executable processes from models defined at a

    higher level of abstraction.

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    IX. CONCLUSIONA main problem in business-to-business applications at a

    large scale, for example at European level, is the

    non-homogeneity encountered both at conceptual and at

    technical levels. This concerns terminology, legislation,

    rules, applications, user interfaces and, last but not least,

    languages used in the daily activities. Service Oriented

    Architecture aims to reduce the collaboration problems andto offer a trustful environment for all actors involved.

    LD-CAST system was designed to offer a common

    framework for business services, realized by automated or

    semi-automated processes, obtained by orchestrating late

    bound Web services. One of the big challenges was to offer

    flexibility in respect with the clients preferences, the national

    practices and the diverse terminologies. The idea was that

    End-Users, even if registered at Local Agencies that may be

    geographically distributed all around Europe, should retrieve

    a friendly system and should pass seamlessly through all the

    necessary steps, for treating their business service requests,

    without perceiving the complexity behind.By describing the Use Case, Process, Logical,

    Implementation and Deployment Views of LD-CAST, the

    paper outlined how SOA, semantic Web and Business

    Process Modeling have been combined for attaining

    requirements that have different priorities for different types

    of actors: user friendliness and security for the End-User,

    maintainability for the Knowledge Engineer, extensibility for

    the Business Process Designer and Service Provider

    Administrator, and traceability for the LD-CAST

    Administrator.

    Moreover, the paper showed the system integration by

    starting from a given use case and then analyzing themappings on all the other views: Logical, Process,

    Implementation and Deployment ones. As SOA also involves

    workflows for orchestrating Web services, the process view

    has an important influence on the other views, imposing:

    logical layers; the presence of specific components for

    modeling, executing and monitoring workflows;

    communication bridges between computation nodes.

    APPENDIX

    One presents below a part of the XML description for the

    Company Legal Verification business service, as transmittedby theBP Modelersubsystem to theRun Time Portal, which

    subsequently displays information to Guests andEnd-Users.

    Company Legal Verification,Italy

    Company legal verification

    Check the legal status of a partner company, in

    order to verify its keeping of the operational current legal

    rules.

    The legal verification includes legal and

    economic/administrative data, such as Registration Number,

    Tax Identification Number, Denomination, Registered

    Office, Statute Information/ Social Pacts, Social Assets,

    Members of Management and their positions, Members of

    Auditing System and holders of other positions or

    qualifications - depending on the country. Various

    certificates supply information about the life and events

    related to the verified company.

    The enterprise certificate of existence, joint

    stock, corporate form; Criminal record; Business History

    Certificates; Business profile information; Certificates of

    non-involvement in organized crime.

    The inputs and outputs differ from one country to another and

    also depend on the organization that supplies the service. The

    exact information may be obtained after registration to

    LD-CAST, through of its Local Agencies.

    ACKNOWLEDGMENT

    We would like to thank to the LD-CAST Consortium,

    including both technical partners and chambers of commerce,for the experience we have gained together related to the

    interoperation between people and software, as well as

    related to the delegation of responsibilities to multiple types

    of users and to developing the correspondent tools. We

    would also like to express special thanks to

    ELSAGDATAMAT (Rome, Italy) for their support during

    the system development.

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